Fig. 3

Lung. A and B The pulmonary parenchyma is effaced and replaced by multiple layers to coalesce, with foci of pyogranulomatous bronchopneumonia consisting of abundant epithelioid macrophages and fewer foamy macrophages containing cytoplasmic, negatively stained bacteria (inset – HE, 60x), and a low number of multinucleated giant cells. Multifocal fibrous bands dissected from the area (A:HE, 10x; scale bar: 200 µm; B:HE, 20x; scale bar: 100 µm). C : Scattered, intramacrophagic and extracellular 1 × 3–4 µm ZN-positive bacilli are present within the granulomas (arrows; ZN, 40x; scale bar: 50 µm)